The present invention relates to climate controls for buildings and particularly to humidity controls. More particularly, the invention relates to humidity controls in conjunction with air handling units.
A large percentage of commercial buildings in the United States utilize Constant Volume Air Handling Units (CVAHU""s) as their HVAC equipment. Also known as prepackaged single zone Roof Top Units (RTU""s), these units may utilize a temperature controller (thermostat) which has the single control input of dry bulb temperature and a single controlled output which is the run time of the equipment. The thermostat may cycle the equipment on and off to regulate the dry bulb temperature of the air in the space. This equipment can have an indirect effect on the humidity in the controlled space during the cooling operation. Since the equipment manufacturers might realize that some moisture removal of the zone air which they are treating may be necessary during cooling season, the temperature of the cooling coils and the (constant) velocity of the air moving across them may be chosen such that a certain percentage of the cooling energy is used to remove moisture. The moisture removal that occurs during RTU run time for dry bulb control, however, may be an indirect result based on assumptions of average air moisture content and equipment run times for dry bulb temperature control of a commercial space and be a function of the cooling coil temperature and constant fan speed chosen. When moisture content is high and/or the thermostat does not run the equipment enough because of low dry bulb conditioning requirements, this indirect control of humidity in the zone is ineffective and the humidity will become too high.
During climate conditions of high humidity levels and relatively warm temperatures in a space, room, enclosure, zone or building, many air conditioners and air handling units have sufficient capacity to cool the space, enclosure or building but are incapable of keeping the humidity of air at a low comfortable level. The problem is readily apparent in the case of rooftop constant volume air handling units in many commercial establishments. Short of replacing the existing units with units with increased dehumidifying capabilities or with dehumidification equipment, there appears to date to be no easy, reasonable and efficient solution.
The present invention may be an easy, reasonable and efficient solution for increasing the dehumidification capabilities of present air handling units including rooftop units. It may involve adding at least one extra air damper actuator, possibly an extra humidity sensor and a controller capable of controlling the various dampers of the system in a manner to further decrease humidity in the space, enclosure or building without modifying or replacing the air handling unit or climate controlling equipment.
The invention may be an apparatus, method or means that utilizes an air handling unit having a cooling mechanism and an air mover. It may have an intake air damper which may be adjusted to effectively change the speed of air movement through the cooling mechanism. It may have at least one humidity detector proximate to the space, room or zone to which the air handling unit is providing climate control. It may have a controller to appropriately control the damper for effecting a sought after humidity level. It may include outside or outdoor air dampers for bringing in outside or outdoor air into the space, room or zone. Also, there may be an exhaust air damper for sending air from the space, room or zone into the outdoor environment. There may be actuators to move the positions of the dampers as indicated by the controller. There may be other air parameter sensors connected to the controller for climate control of the space, room or zone.